I bought an Oracle Alexandria for parts, as the seller claimed the controller AND the motor was burned. As I know it is nearly impossible to burn a Brushless motor, I was confident to be able to repeat it.
After several tests, it was obvious that some parts were burned. The voltage regulator LM317, the input resistor, and capacitor. But the worst part was the CA 3096, a transistor array that is obsolete. 2 transistors in a package were burn, so I replaced them with discrete resistors. To facilitate the tests, I put very high quality sockets everywhere.
But still nothing... The motor refused to work. I used a led and resistor to check any pulse as I didn't have a scope. Strangely enough, when I touch some pins of the arrays, the motor WOULD start to run with noise. So the motor was definitively ok.
After testing everything several times, nothing seems to be done so it SHOULD work... Then, it hit me. I tried another power supply and magically, it works !
So the voltage I was getting was noisy, and the motor would spin from spurious noise generate across the circuit. I opened the power supply box to find.... a non working 1000 Ufd 35 V cap.
I replaced it with a 50 V 3500 ufd, to be safe.
Now the turntable works like a charm.
Any advice on Oracle ? Ask me !!!!
After several tests, it was obvious that some parts were burned. The voltage regulator LM317, the input resistor, and capacitor. But the worst part was the CA 3096, a transistor array that is obsolete. 2 transistors in a package were burn, so I replaced them with discrete resistors. To facilitate the tests, I put very high quality sockets everywhere.
But still nothing... The motor refused to work. I used a led and resistor to check any pulse as I didn't have a scope. Strangely enough, when I touch some pins of the arrays, the motor WOULD start to run with noise. So the motor was definitively ok.
After testing everything several times, nothing seems to be done so it SHOULD work... Then, it hit me. I tried another power supply and magically, it works !
So the voltage I was getting was noisy, and the motor would spin from spurious noise generate across the circuit. I opened the power supply box to find.... a non working 1000 Ufd 35 V cap.
I replaced it with a 50 V 3500 ufd, to be safe.
Now the turntable works like a charm.
Any advice on Oracle ? Ask me !!!!
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@ Serge Dufour,
I have the same problem with my TT. On your picture you replace one resistor in your input board but this is not a resistor, this is a pico fuse (1 A, 125 V). I don't know what is the result if you replace a pico fuse by a resistor.
Anyway, I begin to check my board to try to find the problem...
I have the same problem with my TT. On your picture you replace one resistor in your input board but this is not a resistor, this is a pico fuse (1 A, 125 V). I don't know what is the result if you replace a pico fuse by a resistor.
Anyway, I begin to check my board to try to find the problem...
I think you are wrong.
Show me on the schematic.
If it's the input resistor, 10 ohm,
I'm still right.
---
I'll check the schematic and be back
Show me on the schematic.
If it's the input resistor, 10 ohm,
I'm still right.
---
I'll check the schematic and be back
I checked and you right.
I put a 10 ohm resistor and it works fine.
The problem I had with the board did burn the fuse AND the components AFTER that.
So it was not a reliable protection.
I put a 10 ohm resistor and it works fine.
The problem I had with the board did burn the fuse AND the components AFTER that.
So it was not a reliable protection.
After few tests, it's appear the problem come from the PSU. I replace it by a printer PSU (30vdc) and everythnig work fine.
Cyr-Marc
Cyr-Marc
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